Method of forming end seams in composite containers



March 31, 1953 M r 2,633,095

METHOD OF FORMING END SEAMS IN COMPOSITE CONTAINERS Filed Dec- 28, 1950 2 SHEETS-SHEET 1 1v ENTO i7 Y Z] 00mm 54/1 /2 if is a arm/15 W. 1 /5205 I? 7' TOENEYS .ble seams.

Patented Mar. 31, 1953 METHOD OF FORMING END SEAMS IN COMPOSITE CONTAINERS Donald G. Magill, Great Neck, N. 'Y., and Stanley W.'Pierce, Glen Ellyn, Ill., assignors to American Can Company, New York, N. Y., :acorporation of New Jersey Application December 28, 1950, Serial No. 203,058

The present invention relates to a method of seaming metal end closures onto nonmetallic container bodies, and has particular reference to a method of double seaming wherein the stiff 'metal end is used as a flanging die to produce a fiber body flange of exactly predetermined length and shape.

Heretofore it has not been practical on a truly commercial basis to produce a true double scam in a composite container, 1. e., a container having a fibre body'and metal ends. 'The'm'ain'reason for this has been, that it has not been possible to produce uniform flanges on tubular fibre bodies due to the inherent limitations of the fibrous body materials.

In the handling of tubular metal can bodies, the straight walled bodies usually are fed into a fianging machine wherein opposed flanging dies are forced simultaneously into opposite ends of the body. These dies shape the metal adjacent F the body ends outwardly into stifi flanges which retain their shape until they are interfolded with the cover flanges into double seams. This flanging operation is performed in the can factory and the bottom end closures are usually seamed onto the bodies in the factory immediately thereafter. The bodies, which now have one end closed and one end flanged, are then shipped to the can packing plant where they are filled and sealed. Considerable time may elapse before the bodies are finally sealed, and the body flanges may be subjected to considerable abuse during this time while in shipment and storage. The metal of the can bodies is strong enough, however, to Withstand all normal handling and so this method of handling is practical for metal bodies.

' 'In the case of fibre bodies, however, the situation is somewhat different. The fibrous structure of bodies is such that the material as a rule does not take a permanent set and so the flanges cannot be accurately and uniformly produced.

.Then too, the characteristics of the material are often afiected by moisture and so variations in the humidity in the container factory or packing plant adversely affect the uniformity of the bodyxflanges and so impair the quality of the dou- Furthermore the flanges have-a tendency to straighten out after being formed and cannot be stored for any length of time, and are weak and easily damaged in shipment.

As a result, the trade has never been able to produce a commercially acceptable double seamed composite container. This invention contemplates remedying this situation by making it'possible to produce uniform, accurate flanges at the time the. double seam is formed.

2 Claims. (Cl. 113- 120) An object is to provide a method of forming a double seam between a metal end closure or fitting and a nonmetallic body wherein the metal closure is utilized as a flang'ing die to form an accurate flange of predetermined length in the body at the time the closure and body are assembled.

,A further object is to provide a method of double seaming a metal closure-to a fibre or nonmetallic body wherein the closure curl is utilized to act as a stop to definitely and accurately determine the length of thebody flange.

Another object is the-provision of a method which makes it possible to double seam metal end closures onto container bodies which are made from various types of flexible nonmetallic materials, such as fibre and paper board, plastics, plastic impregnated cloths, etc.

Still another object is to provide a simple method of uniting metal ends to nonmetallic bodies in double seams which "are hermetic and greatly resistant to'internal pressure.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the-following description, which, taken in connection with the accompanying drawings, discloses apreierred embodiment thereof.

Referring to the drawings: 1

Figure 1 is a perspective view of a sealed composite container produced by the method of the instant invention,

Fig. 2 is a side elevation of a fibre container body used in the formation of the composite container of Fig. 1,

Figs. 3 through 6 are sectional views illustrating successive steps in the formation of a double seam by the method of the present invention, parts being broken away,

Figs. '7 through 11, are sectional views similar to Figs. 3 through 6 but illustrate a slightlymodified method of producing a composite double seam, and

Fig. 12 is a side elevation of the fibre container body used in the method illustrated inlFigs. 7 through 11.

As a'preferred or exemplary embodiment of the instant invention, the drawings illustrate method steps of producing-a composite container'having metal ends 21 secured to a fibre body 22 in double seams 23 (see Fig. 1).

For purposes of simplicity, this specification'and the appended claims frequently refer to the body the closure 2|. closure 2| is much stifier and stronger than the many other types of flexible, nonmetallic materials such as plastics, plastic-impregnated cloth, plastic-impregnated glass fibres, etc.

In accordance with the method steps of the invention, the fibre body 22 is first bent or preflanged outwardly to form a slightly flared portion 24 (see Figs. 2 and 3). This flaring operation may be performed in any suitable manner, and the length and angle of the flared portion 24 is not critical, since its function is merely to bias or condition the ends of the body for subsequent outward movement and not to determine the ultimate length of the final flange. After the body has been flared outwardly, it is positioned on a support 30, which, in practice, may be the lifter pad of a double seaming machine. The support 30 is formed with an annular step 3| in order to confine the lower end of the body 22 and prevent any movement thereof while the closure is being seamed on. r The metal end closure 2| is now positioned on the upper end of the body 22 in any suitable manner (see Fig. 3). The end closure 2| is substantially dish-shaped and is formed with a countersunk central panel section 32, adapted to fit within the open mouth of the can body 22. The panel section 32 merges into an upright annular countersink wall 33 having an outside diameter substantially equal to the inside diameter of the body. At its top edge the countersink wall 33 merges into an outwardly extending annular flange 34 which terminates in an open curl 35.

The end closure 2| is held in place by a backing-up chuck 36 which extends downwardly into the countersink of the end closure and engages against the panel section 32 and countersink wall 33. The chuck also extends outwardly a short distance over and against a portion of the annular flange 34 contiguous to the countersink wall. The chuck thus provides lateral support to both countersink wall and flange.

When the body 22 and the closure member 2| have been thus positioned a longitudinal endwise pressure is exerted against the body 22 to move it relative to the closure member 2|. This can be conveniently accomplished by moving the lifter pad 30 upwardly relative to the chuck 35 to compress the body in an endwise direction and force the outwardly turned body end 24 against Since the backed-up metallic fibre body 22, it in effect functions as a nonyielding flanging die. The marginal edge portion of the body is thus forced outwardly and .moves along the lower surface of the closure flange 34 and is progressively reshaped into a body flange 31 (Fig. 4) The body is guided outwardly and prevented from jamming or buckling when it is initially forced against the flange 34 by the outward bias imparted to it by the slight flare 24.

The progressive outward movement of the body edge portion continues until the flange 31 strikes against the inside surface of the open cover curl 35 and is held against further outward movement (see Fig. 4). The curl 35 thus acts as a stop to terminate the flanging operation and predeter mines the width of the body flange 31. The upward movement of the pad 30 is stopped when the body flange 31 hits the cover curl 35, butthe body 22 and the end closure 2| are held clamped together. 5 While the body and closure are thus held, the :interengaged parts of ,the body and the closure are pressed together to form an interfolded double seam 23. This is preferably done in two steps in order to correctly shape the parts. The first step is accomplished by a first operation seaming roll which is pressed against the periphery of the cover to bend the cover flange 34, the cover curl 35, and the body flange 31 downwardly and inwardly toward the body 22 (see Fig. 5). A second operation seamingroll 4|, which diflers in profile from the first operation roll 40, completes the flattening operation and partially embeds the cover curl 35 into the body wall 22 to form a compact, hermetic seam 23 (see Fig. 6). During this operation, the countersink wall 33 is backed-up and supported by the chuck 36.

After the so-calledfactory end closure has been seamed on in the manner just described, the container is shipped to the packing plant, filled, and then sealed by seaming on the second end closure in the same manner. Thus a composite double seam container is produced which is hermetic, highly resistant to internal pressure, and neat in appearance.

Figures 6 through 11 illustrate a slightly modifled embodiment of the invention. Here a straight walled fibre body 22 (see Fig. 12) is used, the preflaring operation being omitted. The countersink wall 33 of the end closure 2|, instead of being vertical as in Figs. 2 through 6, is flared or inclined outwardly to form a conical surface (see Figs. '7 to 9). c

The cover 2|, backed-up by the chuck 36, is positioned in the open mouth of the body 22 (see Fig. 7) and endwise pressure is exerted on the body 22 through the lifter pad 30. This forces the edge of the body 22 against the conical cover surface 50 and imparts an initial outward conditioning flare to it (see Fig. 8). Continued pressure causes the body edge to move or slide along the conical surface 50 and thence horizontally outward along the lower surface of the cover flange 34 until it is stopped by the cover curl 35. Thus a body flange 5| of predetermined length is formed.

The formation of the double seam 23 is completed by the first operation seaming roll 40 (see Fig. 10) and the second operation roll 4| (see Fig. 11) in the manner previously described. The double seam 23 thus formed extends outwardly at an angle from the straight body wall 22 (see Fig. 11) but this flaring does not affect its strength or tightness.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the steps of the process described and their order of accomplishment without departing from .the spirit and scope of the invention or sacrificing all of its material advantages, the process hereinbefore described being merely a, preferred embodiment thereof.

We claim:

l. A methodof forming a seam between a nonmetallic container body and a, metallic end closur having a countersink wall surrounded by an outwardly extending annular flange terminating in an open stop curl, which comprises effecting relative movement between the body and the end closure in an endwise longitudinal direction while laterally supporting said countersink wall and a contiguous portion of said flange to progressively of the body radially outwardly along the closure flange to reshape said edge portion into an outwardly extending body flange, continuing said endwise body movement until the edge of the body flange is stopped by said curl to accurately determine the length of said body flange, and

, folding said body flange and said closure flange downwardly and inwardly to form a double seam.

2. A method of forming a seam between a fibre container body and a metallic end closure having a countersink wall surrounded by an outwardly extending annular flange terminating in a downwardly extending stop curl, which method comprises flaring slightly one end of the body to bias said body end for radially outward movement, moving the body in a longitudinal endwise direction relative to the end closure while laterally supporting said countersink wall and a contiguous portion of said flange to force said flared end of the body along said countersink wall and to progressively force said end of the body radially outwardly along said closure flange to reshape said edge portion into a body flange, continuing said endwise movement until the leading edge of said body flange is stopped by said downwardly extending curl to accurately determine the length of said body flange, and folding said body flange and said closure flange downwardly and inwardly to form a seam.

DONALD G. MAGILL. STANLEY W. PIERCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date Number Name 345,931 'Somers July 20, 1886 568,885 Steward Oct. 6, 1896 1,107,870 Wright Aug. 18, 1914 1,943,568 Ware Jan. 16, 1934 2,164,055 Ellstrom June 27, 1939 2,343,550 Grove Mar. 7, 1944 FOREIGN PATENTS Number Country Date 1,757 Great Britain of 1900 

